The Department of Computer Science at the University of Cyprus cordially invites you to the Colloquium entitled:

JPEG XT: A New JPEG Compression Standard for HDR and WCG Images


Speaker: Dr. Alessandro Artusi
Affiliation: University of Cyprus, Cyprus
Category: Colloquium
Location: Room 148, Faculty of Pure and Applied Sciences (FST-01), 1 University Avenue, 2109 Nicosia, Cyprus (directions)
Date: Friday, November 24, 2017
Time: 15:00-16:00 EET
Host: Yiorgos Chrysanthou (

High bit depth data acquisition and manipulation have been largely studied at the academic level in the last 15 years and are rapidly attracting interest at the industrial level. An example of the high interest for High Dynamic Range (HDR) imaging is the use of 32-bit floating point data for video and image acquisition and manipulation that allows a variety of visual effects that closely mimic the real world visual experience of the end-user. At industrial level, we are witnessing increasing traction towards supporting HDR and Wide Color Gamut (WCG). WCG leverages HDR for each color channel to display a wider range of colors. Consumer cameras are currently available with 14 or 16 bit A/D converter. Rendering devices are also appearing with the capability to display HDR images and video with a peak brightness of up to 4,000 nits and to support wide color gamut (ITU-R Rec. BT.2020) rather than the historical ITU-R Rec. BT.709. This trend calls for a widely accepted standard for higher bit depth support that can be seamlessly integrated into existing products and applications. While standard formats such as JPEG 2000 and JPEG XR offer support for high bit depth image representations, their adoption requires a non-negligible investment that may not always be affordable in existing imaging ecosystems, and induces a difficult transition, as they are not backward compatible with the popular JPEG image format. Instead, most digital camera and mobile phone manufacturers either store images in proprietary RAW formats or, more commonly, offer an HDR mode, which produces a traditional low dynamic range (LDR) image with improved details. In other words, visual information contained in the original high bit depth digital negative is irremediably lost, which is not optimal for editing, creative enhancements, or even viewing on HDR capable display devices. The JPEG XT standard aims to overcome all these drawbacks and to lower the entry barriers to the market. While offering new features, JPEG XT remains backwards compatible with the legacy JPEG standard. As a result, legacy applications can reconstruct an 8-bit/sample LDR image from any JPEG XT codestream. This LDR version of the image and the original HDR image are related by a tone-mapping process that is not constrained by the standard and can be freely defined by the encoder. In this talk the design philosophy behind JPEG XT will be presented. It is a common framework for lossy and lossless representation of WCG and HDR images, which can be seen as a set of various processing tools that can be combined freely. This will be followed by an extensive subjective and objective evaluation of its compression capabilities.

Short Bio:
Dr. Artusi main research activities are in the areas of Image processing, Computer Graphics and Color Science. He has a long standing activities in High Dynamic Range technology, image/video encoding and its standardization, Image content retargeting, energy saving algorithmic solution and image/video subjective and objective evaluation. He has recently initiated deep-learning investigation activities to be applied to typical image processing and computer vision problems. He holds a Ph.D. degree from the Vienna University of Technology, in Computer Graphics, and a MSc. degree in Computer Science from the University of Milano (Italy). He is a member of the IST/037 coding of picture, audio, multimedia and hypermedia information, of the British Standard Institute (BSI), and is acting as UK representative in the ISO/IEC/SC29/WG1/JPEG and ISO/IEC/SC29/WG11/MPEG standardization committee’s. He is one of the editors of the ISO/IEC/18477-JPEG-XT standard, and he has acted as co-chair of the JPEG-XT AhG, and chair of the AhG on verification of the JPEG-XT Part7. For these activities he has been recognized with the prestigious BSI Emerging Standards Maker Award. He recently has received an Associate Professor habilitation from the Agéncia per a la Qualitat del Sistema Universitari de Catalunya (Spain) (AQU) and the Certified Programme I3 (Spanish System). He regularly acts as IPC member and reviewer for major international conferences and journals, and he is the Associate editor of three peer-review international journals. His research activities have attracted more then 1 million of euros, in national and international competitive research funding calls, and he has participated in research projects for a total budget of more then 6.5 millions of euros. He is the co-author of the CRC Press reference book on High Dynamic Range Technology ‘Advanced High Dynamic Range Technology: Theory and Practice’ 1st and 2nd edition and the author of CRC Press book ‘Image Content Retargeting: Maintaining Tone, Color and Spatial Consistency’ For more info visit:

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